Internal coiled tubing connector

ABSTRACT

The present invention generally relates to a connector for coiled tubing that resists torque developed by rotating downhole equipment. The connector couples to an inside diameter of the coiled tubing and can use a torque ring that rotationally locks the connector to the coiled tubing. Additionally, the connector can have a slot on an outside diameter thereof adapted to receive a weld bead on the inside diameter of the coiled tubing in order to rotationally lock the connector to the coiled tubing.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention generally relates to connectors for use with tubular members. More particularly, the present invention relates to a connector for use with coiled tubing that connects to an inside of the coiled tubing and provides torque resistance.

[0003] 2. Description of the Related Art

[0004] Hydrocarbon wells typically involve wellbores that extend from the earth's surface to a selected depth in order to intersect a hydrocarbon bearing formation. Therefore, the wellbores can be several thousand feet in depth. Since tools must be lowered into the wellbore quickly and efficiently, drilling, completion, and production operations often utilize coiled tubing to support the tools used in operations performed within the wellbore instead of jointed pipe or jointed tubing. Therefore, tools connected to the end of coiled tubing include various kinds of downhole equipment tools, bottom hole assemblies, stabilizers, drill motors, and bits. Often times, the coiled tubing must be run through wellbores with restrictions or within other tubulars having a relatively small inside diameter such as production tubing. Therefore, smaller diameter connections between the coiled tubing and the downhole equipment prevent the connections from becoming stuck at a restriction. By engaging the downhole tool to the inside diameter of the coiled tubing instead of the coiled tubing's outside diameter, U.S. Pat. No. 5,251,695 discloses a connector with a smaller outside diameter.

[0005] The ability of the connector to withstand torque is important. If the connector is allowed to spin freely, the downhole equipment runs a high risk of failure. Additionally, rotation between the coiled tubing and downhole equipment can result in the downhole equipment disconnecting from the coiled tubing. The connector in U.S. Pat. No. 5,251,695 fails to withstand torque transmitted to the connection by rotating downhole equipment. U.S. Pat. No. 6,056,051 discloses a slip assembly providing a configuration of rotationally locked slips with wickers to promote resistance of applied torque. However, this connection requires preventing rotation of the slip assembly and internally locking the connector to the slip assembly in order to prevent rotation.

[0006] In the manufacturing of coiled tubing, the coiled tubing is initially a flat piece of metal that is formed into a tubular shape and welded. This process forms a weld bead that typically must be removed from the inside diameter prior to connecting to the coiled tubing. However, removing the weld bead takes time and removes a portion of the coiled tubing that can provide rotational resistance.

[0007] Therefore, there is a need for an improved apparatus that couples downhole equipment to a segment of coiled tubing and also resists the torque that occurs as a result of rotating downhole equipment.

SUMMARY OF THE INVENTION

[0008] A connector for coiled tubing is disclosed that resists torque developed by rotating downhole equipment. The connector couples to an inside diameter of the coiled tubing and can use a torque ring that rotationally locks the connector to the coiled tubing. Additionally, the connector can have a slot on an outside diameter thereof adapted to receive a weld bead on the inside diameter of the coiled tubing in order to rotationally lock the connector to the coiled tubing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

[0010]FIG. 1 is a sectional view of an embodiment of a connector.

[0011]FIG. 2 is a sectional view of the connector coupled to a portion of coiled tubing.

[0012]FIG. 3 is a view of a torque ring on the connector engaged with an end of the coiled tubing.

[0013]FIG. 4 is a view of the connector with a fishing neck partially inserted in the portion of coiled tubing.

DETAILED DESCRIPTION

[0014] Referring to FIG. 1, the connector 100 comprises a mandrel 102, a sleeve 104, a torque ring 106, a slip 108 positioned between a lower slip cone 110 and an upper slip cone 112, a packer 114, and a fishing neck 116. A first end 118 of the mandrel 102 comprises a threaded portion 120 that can be used to attach a downhole tool (not shown) such as a mud motor or any assembly of tools. The fishing neck 116 attached to a second end 122 of the mandrel 102 receives an end portion of coiled tubing (not shown). The mandrel 102 extends through the sleeve 104 so that a relative movement between the mandrel 102 and the sleeve 104 radially expands the slip 108 and places the packer 114 in compression. A thread 124 connects the sleeve 104 to the mandrel 102 and allows the ability to provide the relative movement between the mandrel 102 and the sleeve 104.

[0015] The torque ring 106 circumscribes the mandrel 102 adjacent a lower shoulder 126 created by an end of the sleeve 104. A locking assembly (not shown) such as a slot in the torque ring 106 and a key in the mandrel 102 aligns in order to rotationally lock the torque ring 106 to the mandrel 102. The torque ring 106 comprises a series of teeth 128. Both the lower slip cone 110 and the upper slip cone 112 circumscribe the mandrel 102 adjacent the slip 108 and have a wedge shape with inclined surface 111 and inclined surface 113, respectively. Initially, the slip 108 is in an unexpanded position since the slip 108 is positioned proximate a portion of the upper slip cone 112 having a smaller outside diameter and a portion of the lower slip cone 110 having a smaller outside diameter. An outside diameter of the slip 108 can have formations 109 that grip an inside surface of the coiled tubing (See FIG. 2) to prevent axial movement between the connector 100 and the coiled tubing. The slip 108, upper slip cone 112, and lower slip cone 110 compose a slip assembly 107; however, any slip assembly 107 design that prevents axial movement between the connector 100 and the coiled tubing is within the scope of the invention. As shown, the packer 114 circumscribes the mandrel 102 between an upper shoulder 130 created by an end of the fishing neck 116 and a packing ring 132 adjacent the upper slip cone 112. Alternatively, the packer 114 can be positioned around the mandrel 102 between the slip assembly 107 and the torque ring 106. Preferably, the packer 114 is an elastomeric material that can have a smooth outside diameter surface or an outside diameter surface with formations.

[0016] As shown in FIG. 1, the connector 100 can include the packing ring 132 and a round retaining ring 134 that circumscribe the mandrel 102 between the upper slip cone 112 and the packer 114. The packing ring 132 translates axial movement from the upper slip cone 112 and provides a surface for contacting an edge of the packer 114. Since a portion of the retaining ring 134 contacts a preformed profile 136 around an outside diameter of the mandrel 102, axial movement of the retaining ring 134 relative to the mandrel 102 is limited to a length of the preformed profile 136. A portion of the retaining ring 134 also contacts a shoulder 138 on the upper slip cone 112 in order to prevent axial movement of the upper slip cone 112 past the retaining ring 134.

[0017]FIG. 2 and FIG. 3 illustrate the connector 100 connected to an end portion of coiled tubing 200. However, the connector 100 can be used to connect to an end of any tubing used in a wellbore such as a pipe or any tubular section. As shown, the connector 100 has an outside diameter with no portion substantially greater than an outside diameter of the coiled tubing 200. An end 202 of the coiled tubing 200 is advanced over the fishing neck 116 and the mandrel 102 until the end 202 contacts the torque ring 106. Once the end 202 contacts the torque ring 106, the sleeve 104 is rotated relative to the mandrel 102 in order to axially move the sleeve 104 with respect to the mandrel 102. Therefore, the lower shoulder 126 formed by the end of the sleeve moves axially with respect to the mandrel 102 pushing the torque ring 106 axially in order to engage the teeth 128 of the torque ring 106 with the end 202 of the coiled tubing 200. Engaging the teeth 128 with the end 202 of the coiled tubing 200 provides frictional contact between the teeth 128 and the end 202. Preferably, the teeth 128 at least partially deform the end 202 of the coiled tubing 200 when the teeth 128 engage the end 202. Alternatively, the teeth 128 can embed into or penetrate the metal forming the end 202 of the coiled tubing 200 when the teeth 128 engage the end 202. Once the teeth 128 engage the end 202 of the coiled tubing 200, the teeth 128 prevent rotational movement between the coiled tubing 200 and the connector 100. Since the torque ring 106 is rotationally locked to the mandrel 102 of the connector 100, the connector 100 transfers torque from downhole tools (not shown) to the coiled tubing 200 through the torque ring 106 that resists rotational movement.

[0018] At the same time as the teeth 128 engage the end 202 of the coiled tubing 200, the axial movement of the torque ring 106 caused by the rotation of the sleeve 104 forces the lower slip cone 110 to move axially along the mandrel 102. Since the sleeve 104 moves axially with respect to the mandrel 102, the lower shoulder 126 formed by the end of the sleeve moves axially closer to the upper shoulder 130 that is stationary relative to the mandrel 102. Therefore, the inclined surface of the lower slip cone 110 forces under the slip 108, the inclined surface 113 of the upper slip cone 112 forces under the slip 108, and the packer 114 compresses outward due to a decrease in axial space between the upper shoulder 130 and the packing ring 132. As a result, the outside diameter of the slip 108 contacts an inside diameter 204 of the coiled tubing 200 preventing axial movement between the connector 100 and the coiled tubing 200. The slip 108 can have a C-shape with a longitudinal gap that allows the slip 108 to expand radially as the slip 108 moves up the inclined surfaces 111, 113 to a portion of the slip cones 110, 112 having a larger outside diameter. Once the retaining ring 134 is prevented from further movement along the length of the mandrel 102 due to the preformed profile 136, the upper slip cone 112 is prevented from further axial movement relative to the mandrel 102. Therefore, this limits the axial movement of the packing ring 134 in order to prevent damage to the packer 114 while allowing further compression of the slip assembly 107 since the lower shoulder 126 continues to move closer to the upper slip cone 112 that is held stationary relative to the mandrel 102 by its interaction with the retaining ring 134. Compression of the packer 114 causes the outside diameter of the packer 114 to compress against the inside diameter 204 of the coiled tubing 200 in order to seal an annulus between the inside diameter 204 and the connector 100. The packer 114 can seal an irregular inside diameter 204 of the coiled tubing 200 when compressed. Once the sleeve 104 has been rotated during the operation of the connector 100, a set screw 206 can be advanced to rotationally lock the sleeve 104 to the mandrel 102.

[0019] Furthermore, FIG. 4 illustrates a slot 400 machined along the length of the fishing neck 116 that provides additional resistance against torque between the connector 100 and the coiled tubing 200. The slot 400 receives a weld bead 402 on the inside diameter 204 of the coiled tubing 200 as the coiled tubing 200 advances onto the connector 100. Therefore, the slot 400 allows the fishing neck 116 to slide inside the coiled tubing 200 as it cradles the weld bead 402 to prevent rotation of the coiled tubing 200. Thus, the weld bead 402 acts as a stop once it contacts the slot 400. The slot 400 may additionally be machined to extend through the slip 108, the upper slip cone 112, and the lower slip cone 110 (as shown in phantom) so that the weld bead 402 is cradled throughout the length of the coiled tubing 200 that is positioned around the connector 100. If the coiled tubing 200 design does not include a weld bead 402 (for example, because it was removed in manufacturing), the connector 100 still resists torque through the function of the torque ring 106 acting alone. On the other hand, the slot 400 on the fishing neck 116 when keyed to the weld bead 402 can resist torque acting alone if the connector 100 does not include a torque ring 106.

[0020] Coupling a downhole tool to coiled tubing can be accomplished in a method utilizing the connector 100 as described in FIG. 1 through FIG. 4. Establishing a connection that prevents rotational and axial movement between the downhole tool and the coiled tubing 200 can include positioning the connector 100 proximate the coiled tubing 200, aligning a slot 400 on an outside diameter of the connector 100 with a weld bead 402 on an inside diameter 204 of the coiled tubing 200, engaging teeth 128 of a torque ring 106 with an end 202 of the coiled tubing 200, expanding a slip assembly 107 into contact with the inside diameter 204 of the coiled tubing 200, and connecting the downhole tool to a threaded portion 120 of the connector 100. As a result, the downhole tool is coupled to the coiled tubing 200 by the connector 100.

[0021] While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. 

What is claimed is:
 1. A connector for coupling a tubing to a downhole tool, comprising: a body; a slip assembly operatively connected to the body; and a torque ring operatively connected to the body.
 2. The connector of claim 1, wherein the torque ring comprises a series of teeth adapted to engage an end of the tubing.
 3. The connector of claim 1, wherein the torque ring is rotationally locked to a portion of the body.
 4. The connector of claim 1, wherein the torque ring substantially prevents rotational movement between the connector and the tubing.
 5. The connector of claim 1, wherein the slip assembly substantially prevents axial movement between the connector and the tubing.
 6. The connector of claim 1, wherein a portion of the body is adapted to extend into an inside diameter of the tubing.
 7. The connector of claim 1, further comprising a packer.
 8. The connector of claim 1, further comprising: a packer; and a retaining ring positioned within a preformed profile on the body, wherein the retaining ring limits a compressive force on the packer.
 9. The connector of claim 1, further comprising a fishing neck operatively connected to the body.
 10. The connector of claim 9, wherein the fishing neck comprises a slot along at least a portion of the fishing neck, the slot being adapted to receive a weld bead on an inside diameter of the tubing.
 11. The connector of claim 10, wherein the fishing neck substantially prevents rotational movement between the connector and the tubing.
 12. The connector of claim 1, wherein the body comprises: a mandrel; and a sleeve axially movable relative to the mandrel.
 13. The connector of claim 12, wherein relative movement between the mandrel and the sleeve expands the slip assembly.
 14. The connector of claim 12, wherein relative movement between the mandrel and the sleeve engages at least a portion of the torque ring with an end of the tubular.
 15. The connector of claim 12, further comprising a packer, wherein relative movement between the mandrel and the sleeve subjects the packer to a compressive force.
 16. A connector for coupling a tubing to a downhole tool, comprising: a body; and a fishing neck operatively connected to the body, wherein the fishing neck comprises a slot adapted to receive a weld bead on an inside diameter of the tubing.
 17. The connector of claim 16, wherein the fishing neck substantially prevents rotational movement between the connector and the tubing.
 18. A method for coupling a tubing to a downhole tool, comprising: positioning a connector proximate the tubing; engaging at least a portion of a torque ring with an end of the tubing to prevent rotational movement between the tubing and the connector, the torque ring operatively connected to the connector; expanding a slip assembly into contact with an inside diameter of the tubing to prevent axial movement between the tubing and the connector, the slip assembly operatively connected to the connector; and connecting the downhole tool to the connector.
 19. The connector of claim 18, further comprising aligning a slot on an outside diameter of the connector with a weld bead on the inside diameter of the tubing to prevent rotational movement.
 20. The connector of claim 18, further comprising compressing a packer into contact with the inside diameter of the tubing.
 21. A method for coupling a tubing to a downhole tool, comprising: positioning a connector proximate the tubing; aligning a slot on an outside diameter of the connector with a weld bead on an inside diameter of the tubing in order to prevent rotational movement between the tubing and the connector; expanding a slip assembly into contact with an inside diameter of the tubing to prevent axial movement between the tubing and the connector, the slip assembly operatively connected to the connector; and connecting the downhole tool to the connector.
 22. The connector of claim 21, further comprising compressing a packer into contact with the inside diameter of the tubing. 